ArrayList overwriting entries

Hi Guys,

i'm creating an Java app to add 2 different String values to an ArrayList ( it has to do with my Hobby Badminton )
I now have to following code below:

Code:

---

import java.awt.event.*;
import java.util.ArrayList;
import java.util.Collections;
import javax.swing.*;

public class Badminton implements ActionListener {


        JButton knop1;
        JTextField tekstvak1;
        JTextField tekstvak2;
        JTextField tekstvak3;
        JTextArea uitvoer;
        JButton toernooiButton;
    JButton exitButton;
    JButton zoekButton;
    JButton wisButton;
    ArrayList<String> array1;
        ArrayList<String> array2;
       
       
        private JPanel getContent()
       
        {
                JLabel title = new JLabel ("Badminton Toernooien");
                JPanel bannerpanel = new JPanel();
                bannerpanel.setSize(300,50);
                bannerpanel.add(title);
               
                JLabel toernooiplek = new JLabel("Toernooi plek:    ");
                tekstvak1 = new JTextField(30);
            JPanel plekPanel = new JPanel();
        plekPanel.setLayout(new BoxLayout(plekPanel, BoxLayout.X_AXIS));
        plekPanel.setSize(200, 20);
        plekPanel.add(toernooiplek);
        plekPanel.add(tekstvak1);
   
        JLabel toernooinaam = new JLabel ("Toernooi naam:    ");
        tekstvak2 = new JTextField(30);
        JPanel tekstPanel = new JPanel();
        tekstPanel.setLayout(new BoxLayout(tekstPanel, BoxLayout.X_AXIS));
        tekstPanel.setSize(200,20);
        tekstPanel.add(toernooinaam);
        tekstPanel.add(tekstvak2);
       
        JPanel blankPanel = new JPanel();
        blankPanel.setLayout(new BoxLayout(blankPanel, BoxLayout.X_AXIS));
        blankPanel.setSize(200,20);
       
        toernooiButton = new JButton("Voeg toernooi toe");
        exitButton = new JButton("Afsluiten");
        zoekButton = new JButton("Geef Toernooien weer");
        wisButton = new JButton("Wis invoer");
     
     
        JPanel buttonPanel = new JPanel();
        buttonPanel.setLayout(new BoxLayout(buttonPanel, BoxLayout.X_AXIS));
        buttonPanel.add(toernooiButton);
        buttonPanel.add(exitButton);
        buttonPanel.add(zoekButton);
        buttonPanel.add(wisButton);
       
       
        toernooiButton.addActionListener(this);
        exitButton.addActionListener(this);
        zoekButton.addActionListener(this);
        wisButton.addActionListener(this);
   
       
        JPanel mainPanel = new JPanel();
        System.out.println("JPanel default layout manager = " +
        mainPanel.getLayout().getClass().getName());
        mainPanel.add(title);
        mainPanel.add(tekstPanel);
        mainPanel.add(plekPanel);
        mainPanel.add(blankPanel);
        mainPanel.add(buttonPanel);
        return mainPanel;
       
        }
       
        public void actionPerformed(ActionEvent ae){
                if(ae.getSource() == toernooiButton){
                       
                        String plek = tekstvak1.getText();
                String naam = tekstvak2.getText();
               
                tekstvak1.setText("");
                tekstvak2.setText("");
                       
               
                array1 = new ArrayList<String>();
                array1.add(plek);
                array2 = new ArrayList<String>();
                array2.add(naam);
               
               
                Collections.sort(array1);
                Collections.sort(array2);
               
                JOptionPane.showMessageDialog(null, "Toernooi Toegevoegd");

               
                }
       

                if (ae.getSource()== wisButton){
                        tekstvak1.setText("");
                        tekstvak2.setText("");
                       
                       
                }
               
                if (ae.getSource()== zoekButton){

                               
                        System.out.println(array1);
                       
                       
                        }
                       
                       
                if(ae.getSource()== exitButton){
                        System.exit(0);
                       
                }
        }

        public static void main(String[] args) {
               
                Badminton app = new Badminton();
                JFrame f = new JFrame();
                f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                f.getContentPane().add(app.getContent());
                f.setSize(800,600);
                f.setLocation(200, 200); 
        }
}

---

The problem is that when i want to show the current ArrayList with the "zoekButton" it will give me my last entered input. How can i fix this so that it will list my whole ArrayList?

Thanks in advance

Tom

Every time you click your button you're re-initializing your ArrayList.

Code:

---

array1 = new ArrayList<String>();
array1.add(plek);
array2 = new ArrayList<String>();
array2.add(naam);

---

Move the array1/2 = new ArrayList<String>(); to where you're declaring the list instead.

change

Code:

---

ArrayList<String> array1;
ArrayList<String> array2;

---

to

Code:

---

ArrayList<String> array1 = new ArrayList<String>();
ArrayList<String> array2 = new ArrayList<String>();

---

and then change the first bit of code to

Code:

---

array1.add(plek);
array2.add(naam);

---

Hi kfcSmitty,

I just opened up Eclipse again to adjust it. I tested the code again before adjusting it and i got this error:

Unable to create editor ID org.eclipse.jdt.ui.ClassFileEditor: The Class File Viewer cannot handle the given input

Code:

---

package Final;


import java.awt.event.*;
import java.util.ArrayList;
import java.util.Collections;
import javax.swing.*;

public class Badminton implements ActionListener {


        JButton knop1;
        JTextField tekstvak1;
        JTextField tekstvak2;
        JTextField tekstvak3;
        JTextArea uitvoer;
        JButton toernooiButton;
        JButton exitButton;
        JButton zoekButton;
        JButton wisButton;
        ArrayList<String> array1 = new ArrayList<String>();
        ArrayList<String> array2 = new ArrayList<String>();
       
       
        private JPanel getContent()
       
        {
                JLabel title = new JLabel ("Badminton Toernooien");
                JPanel bannerpanel = new JPanel();
                bannerpanel.setSize(300,50);
                bannerpanel.add(title);
               
                JLabel toernooiplek = new JLabel("Toernooi plek:    ");
                tekstvak1 = new JTextField(30);
                JPanel plekPanel = new JPanel();
        plekPanel.setLayout(new BoxLayout(plekPanel, BoxLayout.X_AXIS));
        plekPanel.setSize(200, 20);
        plekPanel.add(toernooiplek);
        plekPanel.add(tekstvak1);
   
        JLabel toernooinaam = new JLabel ("Toernooi naam:    ");
        tekstvak2 = new JTextField(30);
        JPanel tekstPanel = new JPanel();
        tekstPanel.setLayout(new BoxLayout(tekstPanel, BoxLayout.X_AXIS));
        tekstPanel.setSize(200,20);
        tekstPanel.add(toernooinaam);
        tekstPanel.add(tekstvak2);
       
        JPanel blankPanel = new JPanel();
        blankPanel.setLayout(new BoxLayout(blankPanel, BoxLayout.X_AXIS));
        blankPanel.setSize(200,20);
       
        toernooiButton = new JButton("Voeg toernooi toe");
        exitButton = new JButton("Afsluiten");
        zoekButton = new JButton("Geef Toernooien weer");
        wisButton = new JButton("Wis invoer");
     
     
        JPanel buttonPanel = new JPanel();
        buttonPanel.setLayout(new BoxLayout(buttonPanel, BoxLayout.X_AXIS));
        buttonPanel.add(toernooiButton);
        buttonPanel.add(exitButton);
        buttonPanel.add(zoekButton);
        buttonPanel.add(wisButton);
       
       
        toernooiButton.addActionListener(this);
        exitButton.addActionListener(this);
        zoekButton.addActionListener(this);
        wisButton.addActionListener(this);
   
       
        JPanel mainPanel = new JPanel();
        System.out.println("JPanel default layout manager = " +
        mainPanel.getLayout().getClass().getName());
        mainPanel.add(title);
        mainPanel.add(tekstPanel);
        mainPanel.add(plekPanel);
        mainPanel.add(blankPanel);
        mainPanel.add(buttonPanel);
        return mainPanel;
       
        }
       
        public void actionPerformed(ActionEvent ae){
                if(ae.getSource() == toernooiButton){
                       
                String plek = tekstvak1.getText();
                String naam = tekstvak2.getText();
               
                tekstvak1.setText("");
                tekstvak2.setText("");
                       
               
                array1 = new ArrayList<String>();
                array1.add(plek);
                array2 = new ArrayList<String>();
                array2.add(naam);
               
               
                Collections.sort(array1);
                Collections.sort(array2);
               
                JOptionPane.showMessageDialog(null, "Toernooi Toegevoegd");

               
                }
       

                if (ae.getSource()== wisButton){
                        tekstvak1.setText("");
                        tekstvak2.setText("");
                       
                       
                }
               
                if (ae.getSource()== zoekButton){

                               
                        System.out.println(array1);
                       
                       
                        }
                       
                       
                if(ae.getSource()== exitButton){
                        System.exit(0);
                       
                }
        }

        public static void main(String[] args) {
               
                Badminton app = new Badminton();
                JFrame f = new JFrame();
                f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                f.getContentPane().add(app.getContent());
                f.setSize(800,600);
                f.setLocation(200, 200); 
        }
}

---

I changed the code in my Badminton class to

Code:

---

ArrayList<String> array1 = new ArrayList<String>()
ArrayList<String> array2 = new ArrayList<String>();

---

but i don't know exactly where i need to put the

Code:

---

array1 = new ArrayList<String>();
array1.add(plek);
array2 = new ArrayList<String>();
array2.add(naam);

---

I understand now what the problem is , but not totally how i need to fix it.
Thanks for your fast response

Tom

This code

Code:

---

array1 = new ArrayList<String>();
array1.add(plek);
array2 = new ArrayList<String>();
array2.add(naam);

---

Is already in your program, if you search for it, you'll find it. What you need to do, is remove these two lines from the above code

Code:

---

array1 = new ArrayList<String>();
array2 = new ArrayList<String>();

---

Which will leave you with

Code:

---

array1.add(plek);
array2.add(naam);

---

ah ok fixed it now, but the program won't start because of that error:

The Class File Viewer cannot handle the given input ('org.eclipse.ui.ide.FileStoreEditorInput').

Do you know how to fix that error, didn't had it before

Thanks for the fast feedback

Tom

ok i fixed that error by putting in

Code:

---

f.setVisible(true);

---

But no i get this when i click the toernooiButton:

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at Final.Badminton.actionPerformed(Badminton.java:94)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

Ok,

the problem is this piece of code

Code:

---

array1.add(plek);
array2.add(naam);

---

if i delete it it runs, but not properly.
Do you know where i need to put it / change it.

ok guys,

solved the problem, it was the start of the code.
The lines

Code:

---

    ArrayList<String> array1 = new ArrayList<String>();
ArrayList<String> array2 = new ArrayList<String>();

---

I forgot those.

kfcSmitty, thanks for your help

Tom